It isn't, really. That the entire point. Just repeating that it is without actually making a _science_ based argument is plain silly. If you inject yourself with non-sterile material, there is an extremely high chance you will now die from two things (or more), instead of just one. Depending on the organism, an untrained person attempting to grow bacteria outside of a lab might create an even bigger problem, for e.g. if they improperly dispose of it, the organism (or other metabolites/proteins/etc) could leech into the soil and cause further damage, or worse.. contaminate the water supply. Heck the city won't even let you install a sprinkler without making sure you're not sending the water back into the supply. And you guys are thinking about growing bacteria at home. I don't think I can make my case any clearer. This is a terrible idea. But OK, you do you...